An Inca city on the saddle between two peaks at eight thousand feet, built around 1450 and abandoned perhaps a century later — probably to smallpox, which arrived ahead of the Spaniards themselves. The conquistadors never reached it and never learned it was there. The stones are fitted without mortar so closely that a knife blade will not go between them, and the Intihuatana, a carved pillar, casts almost no shadow at the solstices.

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The Askinskaya Ice Cave

A cave in Bashkortostan with a single chamber holding ice columns up to eleven metres tall, grown over centuries. The temperature stays below freezing all year: cold air flows in during winter and cannot get out. Bashkir tradition places a guardian spirit here, to whom offerings were left at the mouth. In the 2010s visitor numbers damaged some of the columns and the cave was closed to open access.